The subject invention is directed generally to test circuitry for integrated circuits, and more particularly to built-in test circuitry that provides for in-system isolation of a stuck driver on a multi-driver bus.
By use of known fault detection techniques including boundary scan, integrated circuit output faults are detected, and many possible faults can be isolated by analyzing the logical states of nodes at particular times with the knowledge of what logical levels are expected. However, isolation of a faulty output driver responsible for a multi-driver stuck-at fault, wherein the logical level of a node is stuck-at a particular logical level, is presently accomplished pursuant to one-by-one removal of each driver from a node and checking to see if the node becomes unstuck.